Radon indoor air

Problems that rank relatively high in cancer and non-cancer health risks but low in ecological and welfare risks include hazardous air pollutants, indoor radon, indoor air pollution other than radon, pesticide application, exposure to consumer products, and worker exposures to chemicals... 

Cancer registries (http //www.cdc.gov/cancer/npcr/) Radon, indoor air quality (http //www.ehso.com/ ehshome/radon.htm)... 

Applications. Both industrial emissions reduction and indoor air-poUution abatement uses will grow. For example, the development of adsorbents with higher capacity for removal of radon from humid air could allow the development of a one-bed, delay-for-decay system in which radon adsorbs, decays to lead, and is precipitated onto the adsorbent. 

Airborne material affecting the quality of indoor air may be classified as gases or particulate matter. Gases which may be potential problems are radon, CO, NOj, and hydrocarbons. Particulate matter may come from tobacco smoke, mold spores, animal dander, plant spores, and others as shown in Table 23-1. Other factors interact to influence our perception of indoor air quality, including humidity, temperature, lighting, and sound level. 

Effects of indoor air pollutants on humans are essentially the same as those described in Chapter 7. However, there can be some additional pollutant exposures in the indoor environment that are not common in the ambient setting. From the listing in Table 23-1, radon exposures indoors present a radiation hazard for the development of lung cancer. Environmental tobacco smoke has been found to cause lung cancer and other respiratory diseases. Biological agents such as molds and other toxins may be a more likely exposure hazard indoors than outside. 

Nazaroff, W. W., and Teichmann, K., Indoor radon. Environ. Sci. Technol. 24, 774-782 (1990). U.S. Environmental Protection Agency and U.S. Consumer Product Safety Commission, "The Inside Story A Guide to Indoor Air Quality." EPA/400/1-88/004, September 1988. 

Outdoor inhalation exposure is mainly due to traffic, energy production, heating, and natural factors such as pollen and mineral dusts. These outdoor sources of pollution also affect indoor air quality. The indoor concentration is typically 20-70% of the corresponding outdoor concentration. Occasionally the indoor concentrations of an external pollutant (especially radon) may even exceed the concentrations outdoors. ... 

As the science of indoor air quality has matured, indoor air professionals have realized that many indoor air contaminants and the associated health effects are linked to specific types of buildings and their characteristics. For example, radon is primarily an indoor air concern in homes because of the ease with which it can be transported inside residential construction from the soil beneath. On the other hand. Sick Building Syndrome (SBS) primarily afflicts office building occupants who experience acute health and comfort effects that appear to be linked to time spent in a specific building. 

The most common way radon enters a building is when lower indoor air pressure draws air from the soil, bedrock, or drainage system into the house. If there is radon in the soil gas, it will also be drawn in. Just as gravity will make water flow from a high elevation to a lower elevation, pressure differences will make radon-laden air move from an area of higher pressure to an area of lower pressure. For a variety of reasons, most buildings tend to maintain an indoor air pressure lower than outdoor air pressure. If cracks and holes in the foundation are open to the soil, radon will be drawn indoors. Radon movement by pressure differences is called pressure-driven transport. 

Like most other indoor air contaminants, radon can be controlled by keeping it out of the house, or reducing the concentration by mixing it with fresh air after it has already entered. The following approaches have been tried or suggested9 ... 

The major drawback to using the Florida study to support the correlation between indoor and soil measurements was that the indoor measurements were obtained from 3-day closed-house charcoal measurements, and soil radon was obtained from 1-month alpha track measurements buried 1 ft beneath the soil surface. Comparisons of charcoal and alpha track data are generally not recommended since they are quite different measurement techniques, and represent radon levels over different time periods. However, the study was subjected to numerous quality control checks including deployment of alpha track detectors in 10% of the houses to obtain a check on indoor air measurements made by charcoal canisters. In spite of the measurement drawbacks, the study indicates that soil radon measurements taken alone are not a dependable predictor of potential indoor radon concentration. 

To summarize, a mechanical system that is planned to control indoor air contaminants (including humidity, radon, combustion gases, and body odors) and reduce the risk of condensation in the building shell in a cold humid climate should include... 

Osborne, M.C., Resolving the radon problem in Clinton, NJ, houses, in Indoor Air 87 Proceedings of the 4th International Conference on Indoor Air Quality and Climate, Vol. 2, Berlin, Germany, pp. 305-309, August 1987. 

The physico-chemical properties of radon and its decay products are presented in a series of reports primarily focusing on the decay products. However, Stein (1987) presents a review of his pioneering studies of radon chemistry and the reactions of radon with strong oxidizing agents. Although radon is not chemically active in indoor air, it is interesting to note that radon is not an "inert gas. 

Jonassen, N. and J.P. McLaughlin, The Reduction of Indoor Air Concentrations of Radon Daughters Without the Use of Ventilation,... 

Wilkening, M., Effect of Radon on Some Electrical Properties of Indoor Air, this volume (1987). 

Swedjemark, G.A. and MjOnes, L. Exposure of the Swedish population to radon daughters, in Proceedings of the 3rd International Conference on Indoor Air Quality and Climate, Stockholm, 1984, 2, pp. 37-43, Swedish Council for Building Research, Stockholm (1984). 

Swedjemark, G.A., Limitation schemes to decrease the radon daughters in indoor air, Report 86-01, National Institute of Radiation Protection, Stockholm (1986). 

Figure 3 Radon concentration in the indoor air of detached houses. The size of the symbol indicates the magnitude of the local geometric mean. Measurements have been made in about 4,450 houses in 183 localities.

Indoor air radon concentrations measured in a randomly selected sample of 220 Irish houses have been found to range from about 20 Bq/nr to as high as 1740 Bq/nr with a median value of 61 Bq/nr. Using current dose estimation methods the estimated effective dose equivalents due to radon daughter inhalation in these houses are 1.6 mSv/year (median value) and 46 mSv/year (maximum value). 

In the radon surveys the primary quantity determined is the indoor air mean radon activity concentration. From a radiological health perspective it is the dose arising from the inhalation of radon daughters that is of interest. The conversion from radon exposure to annualised effective dose equivalent for the survey was carried out using the factors given in Table I which are similar to those being used in other European surveys. The occupancy and equilibrium factors given in this table are assumed mean values for Irish... 

The national indoor air radon survey commenced in the autumn of 1985. In this first phase of the work radon detectors were sent to 400 randomly selected households throughout Ireland, A further 400 households are scheduled to receive detectors by the end of April 1986. At the time of writing radon detectors from a total of 220 households have been recovered and processed. The principal results obtained are shown in Table II, together with the results of the earlier pilot survey and the cumulative results for both sets of data. 

Porstendorfer, J., Behaviour of Radon Daughter Products in Indoor Air, Radiation Protection Dosimetry 7 1 (1984). 

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